Piston engine



June 29, 1937. J. PAvLEcKA 2,085,270 PIsToN ENGINE Filed Nov. 22, 19:55

1N VENTOR.'

Patented June i937 iran stares rarest ortica 35 Claims.

My invention relates to a novel internal combustion or steam engineemploying a number of pairs of oppositely moving pistons.

The object of my invention is to devise a compact, light and smoothrunning engine of the above species.

Another object is to provide an engine in which a large number ofpistons is actuating a least number of cranks for concentrationof powerand smoothness. l

A still further object is to devise an engine in which the usualcylinder head, which is a heavy and unsafe member in any engine, iseliminated, and in which inertia forces are inherently balanced. y

These and other objects and aims of my in` vention are realized,broadly, by making use of .at least three power unitsor cylinders openat both ends, each unit comprising a pair of opposed pistons providing acommon combustion or compression chamber therebetween, and 'disposingsaid units in one plane in such a manner that each two contacting unitswill actuate a common crankshaft.

The manner in which thisprlnciple is materialized will now be disclosedin the following description which presents a few illustrativeembodiments of the invention one of which is referred to as thepreferred one. In this descrip- 3f), tion reference is` taken tothedrawing which forms an integral part of this specification, and inwhich Fig. l is a cross-section through the preferred form of the enginedisclosing, among other fea- 3 ,.tures, three power units and threecrankshafts,

all in one plane. l

Fig. 2 is a cross-section through another em` bodlment of my invention,this one consisting of four power units and four cranks in one plane.

Fig. 3 represents a perspective view of the engine in Fig. 1, showing,by way of example, four banks of power units arranged side by side, andinduction and timing means therefor.

Fig. 4ris a sectional elevation through an en- 45 gine analogous in allways to that in Fig. 1 but having outwardly pointed power units.

The embodiments in Figs. 1, 2 and 4 demonstrate the extent within whichmy invention is purviewed, Figs. 1 and 4 being representative of :m theleast number of powerunits-three-in one plane, while Fig. 2 illustrateswhat I consider the largest practical number of power ,units in oneplane, i. e., four. l

Referring to all four figures, the engine of 5.3 my inventiomin itsvarious forms, comprises at least three cylindrical or tubular powerunits in one plane and equallyas many cranks, and any number of likepower units disposed in like planes side by side. My invention residesparticularly in the relative assembly of the three or more power unitsand the cranks in one plane and in the angular relationship between eachtwo associated power units, and an engine embodying the same may bedefined broadly as consisting sentially of at least three engines of thewell-known V-type disposed inversely lto each other whereby the twocylinders in each V will be conjoined with corresponding cylinders ofthe associated V or Vs ln e. common combustion 'or pressure chamber;each two cylinders thus conjoined produce one tubular or cylindricalpower unit with two opposed pistons therein. The angle between thecylinders in, the Vs of which my new engine is constituted may,obviously, be of any practical value, the most desirable congurationsbeing those in which the included angle between each two associatedcylinders is substantially less than 90 degrees for reasons disclosedhereinfurther, and more particularly those in which the cylinders of themerged Vs are alined axially into straight cylindrical power units, asin Fig. 1.

Conforming to the above disclosure, the embodiment in Fig. 1 may bedefined as derived from three V-type engines disposed inversely to eachother and united at their cylinder extremity into a single power plantwherein two pistons, one from each two united cylinders, share the samecombustion or pressure chamber.'

The resultant engine comprises three cylindrical power units I3, lil andl5 that, in this particular and preferred embodiment, and rectilinearbetween their axial open ends and conjointly form an equilateraltriangle in one plane; inthe corners of this triangle at the opencontacting ends of each two associated power units are disposed thecranks le, il and i8 which rotate in the plane of the triangle andaxially 'are perpendicular to it. In this embodiment, as in anyotherembodiment of my invention, the number of the cranks is equal to thenumber of power units in one plane, three in this case. In each of thepower units i3 to l5 reciprocate the twin .pistons 3 and tl in generallyopposite directions and provide the compression or pressure chamber 8between them.- Each of the twin pistons 3 and d is operativelyjournalled, as by the connecting rods 20 and l respectively, to twodifferent cranks, in consequence of which each of the cranks i t to iBwill have two pistons,

' either the articulated type; i. e., one pinned to the other, or asshown, one of them, I9, may be forked and made to straddle the otherone, 28, on the crank pin.

The cranks I6 to I8 pert-ain to as many crankshafts which are timedrotationally out-ofphase so that the pistons 3 and 4 in each power unitwill travel in opposite directions throughout the major portion of theirstroke, and in the same direction throughout the remainder of it forreasons of improving the working cycle of the engine as disclosedhereinfurther. 'This timing is accomplished, by way of example, by meansof the gears 2'I, 28 and 29 at the endls of the crankshafts to which thecranks I6 to I8 appertain, al1 three of said gears engaging the centralgear I0 on the driving or driven shaft I2. The engine in Fig. 1 is aninternal combustion engine, and is intended to operate on the twocycleprinciple without any valves. To this end, the power units I3, I4 and I5are provided each with the intake port or ports 2| and the exhaust portor ports 22, said intake ports being located at the end of the stroke ofone of the pistons 3, while said exhaust ports are located at the v'endof the stroke of the twin piston 4. The intake ports 2| in all threepower units communicate through passages 24 with the induction duct 23which is located centrally in the triangular space between the powerunits, and lis fedv forcibly from one of its axial ends. 'I'he exhaustports 22 open outwardly from the power units into the manifolds 25. Ineach power unit is inserted the ignition plug or injection valve 26.

The charge of air, or of air and fuel, enters the power units at one endof the space displaced by the pistons 3 and 4 when these pistons areapproximately furthest apart whilesimultaneously proceed in the samedirection without intermixing. v

Inasmuch as the exhaust and intake ports in the power units arecontrolled by the movements of the twin pistons therein, thenyby'staggering said pistons in their reciprocal movements so that the onewhich controls the exhaust port will arrive at the end of its strokeearlier than the other piston, the burnt gases will be discharged beforea new charge arrives, and at the other end the intake port will still beuncovered while the exhaust port is already partly or fully closed,thereby allowing Y- for supercharging to take place. f Theseasynchronous movements of the 'twi pistons 3 and 4 in each power unitvare readily "obtainable in any embodiment of the engine of my inventionby gearing the cranks so that they will all rotate in the same angulardirection, in

' which case they will be closest to one another at the moment theycoincide with the line of symmetry between twopower units and not wheneither of them reaches the top dead center with respect to one of thepower units.4 'I'hus in Fig.

1, due to the fact that the gears 21, 28 and 29 enthereof and made thedead center of the associated unit I4; the same angular advance of onecrank over the other is evident in the other two power units I3 and I4.

The significance of the out-of-phase movements of the cranks I6, I1 andI8, and the consequent asynchronous movements of the pistons 3 and 4 ineach power unit, resides in that the piston 4 will precede its twin 3 byan interval which is proportional to the angle included between any twoassociatedpower units I3 to I5, and will open and close theexhaust ports22 before said piston 3 opens andcloses the intake ports 2|, therebyaffording the aforementioned functional advantages in the working cycleof the engine.

The arc on the crank orbit by which the cranks and the pistons in theengine of my invention are out of phase is determined by the angleincluded 'between each two contacting power units; in the triangularembodiment in Fig. 1 this angle is 60, which denotes that the exhaustports 22 will be opened and closed that many degrees of crank travelsooner than the intakeports 2l provided, of course, that they are of thesame size and in a corresponding opposite location, While piston engineswith power units having an included angle of as many as 90 degrees oreven more are feasible, I prefer to direct my claims specifically .topiston engines wherein the included angle between each two associatedpower units is substantially less then 90 degrees since an angle greaterthan this number entails an excessive out-ofphase movementof the twinpistons in the power units with consequent destruction of dynamicbalance and impractical timing of intake and exhaust.

In an engineconsisting of a number of power units in one plane andworking on the two-cycle,

principle, as the one in Fig. 1, the combustion occurs simultaneously inall the power units when the pistons therein are closest to each other,which is when the cranks fall on the line of symmetry between the powerunits. In order toobtain a more even torque outputin such an engine,-

any number of power units forming a bank like the one in Fig. 1, or inFigs. 2 and 4, may be disposed side by side and the pistons thereinjournalled to the same crankshafts each of which has as many cranks asthere are banks in the engine.

Such an engine is shown in Fig. 3,this one being composite of four banksof power units.such as shown in Fig. 1; the crankshaft, the connectingrods and the pistons on the near side are removed to reveal the powerunits I4y and I5. At one axial end of the engine is disposed the centraldriven gear I0 on the shaft .-I2, and-.around it the gears 21, 28 and 29'(gear 28 being removed) on the respective crankshafts. At the oppositevend of the engine is mounted the air blower 30 which is shown as being,by way of example, of the centrifugal type, driven from one of thecrankshafts through thegear 35 and a pinion not visible in thisview.'I'he blower 30 has the air intake 3I and the air discharge 32, thelatter registering with the central induction duct 23 of Fig. 1 anddelivering air thereinto.

The embodiment in Fig. 4 illustrates further the above denition that anengine of my invention may generally be c onsidered as derived from aplurality of V-type engines, three in this ease; the resultant tubularpower units 33 are not, however, rectilinear as those in Fig. 1, but areoutwardlypointed in mid-length the included anglebetween the A,powerunits being substantially less aosaaro than 90 degrees; they couldequally Well be pointed inwardly. 'Ihe cranks i6, il and I8 are shown,similarly as in the previous embodiment, as being timed out of phase,which causes the pistons 3 and in each power unit 33 to reciprocateasynchronously.

Although the embodiment in Fig. l has been referred to as the preferredone, it does not imply that it represents an ultimate practical numberof power units that can be combined in one plane and made to operate anequal number of crankshafts according to the principles of out-of-phasetiming as set forth hereinabove. Fig. 2 presents an embodimentcomprising four power units, 36, the units being pointed inwardly inmidlength whereby each two associated power units include an angle ofsubstantially less than 90 degrees between them. Similarly as in thepreceding embodiments-this engine may be deiined as being constituted byfour V-type engines sharing their combustion or pressure extremities;the resultant power units jointly form. a generally polygonal pattern inone plane in four corners of which are located the four cranks d8 tofil. To each crank are joui-nailed, as Aby connecting rods i9 and 20,two pistons 3 and one from each two contacting power units. Theembodiment in Fig. 2 is shown as characterized by the same out-of-phasetiming of the cranks and asynchronous movements of the pistons as theengines of Figs. land 4, i. e., all four cranks E8 'to 5! rotate in thesame angular direction as indicated-b-y arrows due to the fact that theyare gearedv by pinions 36 to 39, respectively, to the one central gearl0 on the drive shaft i2. The angular shift of substantially less than90 degrees in the relative positions of the two cranks operating any onepower unit 3d will provide the same disharmonious movements of the twinpis'- tons 3 and i therein within practical limits for reasons'ofimp-roving the working cycle of the engine as disclosed hereinabove.

I claim:

l. In a piston engine in combination in one plane, threecylindersdisposed to forman equilateral triangle, two opposed pistons ineach of said cylinders, and three cranks disposed apiece in the cornersof said triangle, each crank having two pistons, one from each twoassociated cylinders, operatively journalled thereto.

2. In a piston engine in combination in one plane and in any num-ber oflike planes side by side, three tubular power units, three cranks, andsix pistons in said power units, said power units being disposed to havethe axes thereof intersect, said cranks being located apiece at theintersections of said axes, and said pistons being operativelyjournalled to said cranks in pairs whereby two pistons journalled to.two different cranks will face each other in each power unit.

3. In a piston engine in combination in one plane and in any number oflike planes side by side, three tubular power umts, three pairs ofopposed pistons, and three cranks, said power units being disposed tohave the axes thereof in- Atersect and each comprising one of said pairsof pistons, said cranks being located apiece at the intersections ofsaid axes whereby two pistons from two different power units will beoperatively journalled to each crank; and means for transmitting powerfrom said cranks to one shaft and for timing said cranks in rotation tocause said pistons in each power unit to reciprocate in generallyopposite directions.

4. In a piston engine in combination in one plane and in any number oflike planes side by side, three tubular power units having intake andexhaust ports therein, three cranks, and six pistons, said power unitsbeing disposed to have the axes thereof intersect, said cranks beinglocated apiece at the intersections of said axes, said Apistons beingoperatively journalled to said cranks in pairs whereby twopistonsjournalled to different cranks will face each other in each power unitand will control said ports therein; and an induction manifold, saidmanifold comprising a central duct in the space between said power unitsand passages branching from 'said duct and connecting tovsaid intakeports in said power units.

5. A piston engine comprising, three tubular power units havingintersecting axes in one plane, any number of like power units in likeplanes side by side, said power units having intake and exhaust portstherein, two pistons in each of said power units controlling said ports,three crankshafts disposed apiece at the intersections of said axes andhaving each a crank in the plane of said power units, each crank havingtwo pistons, one from each two associated power units, operativelyjournalled thereto, three driving gears mounted apiece at one end ofsaid crankshafts, a driven gear supported on a central shaft, saiddriving gears engaging with said driven gear and being timed thereby soas to make said pistons in each power unit reciprocate in oppositedirections throughout a major portion of their stroke, and an inductionmanifold disposed between said power units and connecting to said intakeports therein, said manifold having an entrance at the end opposite saidgears.

6. In a piston engine in combination in one plane, at least threetubular power units disposed to form a closed pattern, two opposedpistons in each of said power units, and a number of cranks equal to thenumber of said power units disposed apiece in the corners of saidpattern, each crank having two pistons, one from each two associatedpower units, operatively journalled thereto, said power units beingdirected axially between the ends thereof so that the angle included byand between each two associated power units in said pattern will be lessthan 90 degrees.

7. In a. piston engine in combination in one plane, at least threetubular power units disposed to form a. closed pattern, two opposedpistons in each of said power units, and a number of cranks equal to thenumber of said power units disposed apiece in the corners of saidpattern, each crank having two pistons, one from each two associatedpower units, operatively journalled thereto, the angle included by andbetween each two associated power units in said pattern beingapproximately 60 degrees.

8. In a piston engine in combination in one plane, three tubular powerunits disposed to form a closed pattern, two opposed pistons in each ofsaid power units, and three cranks disposed apiece in three corners ofsaid pattern, each crank having two pistons, one from each 'twoassociated, power units, operatively journalled thereto, said powerunitsbeing bent in midlength whereby the angle lincluded by and between eachtwo associated power units in said pattern will be of any desirablemagnitude besides 60 degrees.

9. In a piston engine in combination in one plane, four tubular powerunits disposed to form a closed pattern, two opposed pistons in each ofsaid power units, and 4four cranks disposed apiece in four corners ofsaid patterns, each crank hav- `ingtwo pistons, one from each twoassociated power units, operatively journalled thereto, said power unitsbeing bent inwardly in midlength whereby the angle included by andbetween each two associated powerv units in said pattern will be of anydesirable magnitude smaller than 90 degrees.

10. In a piston engine in combination in one plane, at least threetubular power units disposed to form a closed pattern, two opposedpistons in each of said power units, and a number of cranks equal to thenumber ofsaid power units dispos-ed apiece in the corners of saidpattern, each crank having two pistons, one from each two associatedpower units, operatively journalled thereto, -said cranks being timed toreach simultaneously the dead center with respect to different powerunits whereby the twin pistons in each power unit will reciprocateasynchronously within a limited number of degrees of crank rotation,said power units being directed axiallybetween the ends thereof so thattheangle included by and between each two associated power units in saidpattern will be smaller` than 90 degrees toprovide said limitedasynchronous movements of the pistons.

11. In a piston engine in combination in one plane, at least three.tubular power units disposed to form a closed pattern, two opposedpistons in" each of said power units, and a number of cranks equal tothe number of said power units disposed apiece in the corners of saidpattern, each crank having two pistons, one from each two. associatedpower units, operatively journalled thereto, said cranks being timed torotate in the same angular direction in a manner whereby one crank willbe on the dead center with respect to one power unit while the crank towhich the twin piston in the same power unit is journalled will be onthe corresponding dead center of the associated power unit, said powerunits being directed axially betweenthe ends thereof so that the angleincluded by and between each two associated power units in said patternwill be smaller than 90 degrees to limit the unbalanced' forces andout-of-phase movements of said twin pistons'. x

12. In a piston engine in combination vin one lplane, three tubularpower units disposed to form a closed pattern, .two opposed pistons ineach of nalled thereto, said cranks being timed to reach simultaneouslythe dead center with respect to "different power units whereby the twinpistons in each power unit will reciprocate out-of-phase, said powerunits being pointed .in midlength whereby theangle included by andbetweenveach ,two associated lpower units in said pattern will be of anydesirable magnitude smaller than 90l said -cranks having two pistons,one from eachtwo associated power units, operativelyjours nalledthereto, said cranks being timed to reach simultaneously the dead centerwith respect to different power units whereby the twin pistons in eachpower unit will reciprocate out-of-phase, said power units being pointedinwardly in midlength whereby the angle included by and be. tween eachtwo ,associated power units in said pattern will be smaller than 90degrees to limit the unbalanced forces and said out-of-phase movementsof said twin pistons.

14. In a piston engine in combination in one plane, three cylindersdisposed to form an equilateral triangle, two opposed pistons in each ofsaid cylinders, and three cranks disposed apiece in the corner of saidtriangle, each crank having two pistons, one from each two associatedcylinders, operatively journalled thereto, said cranks being timed torotate .all in the same angular direction in a manner whereby one crank'will be on the dead center with respect to one cylinder while the crankto which the twin piston in the same cylinder is journalled will be onthe corresponding dead center with respect to the associated cylinderwhereby said twin pistons in each cylinder will reciprocate out-ofphaseby 60 degrees of crank rotation.

' 15. In a. piston engine in combination in one plane, at least threetubular power units disposed to form a closed pattern, said power unitshaving intake and exhaust ports therein, two opposed pistons in each ofsaid. power units controlling said ports therein, a number of cranksequal to the number of vsaid power units disposed in the corners'ofsaidpattern, each crank having two pistons, one from each two associatedpower units, operatively journalled thereto, said cranks being timed toreach simultaneously the dead center with'respect to different powerunits whereby the piston controlling said exhaust port in any one powerunit will precede the twin piston controlling said intake port by alimited interval, said power units being directed axially between theends thereof so that the angle included by and between each twoassociated power units in said pattern will be smaller than 90 degreesto provide said limited interval.

16. In a piston engine in combination in one plane, three tubular powerunits disposed to form a closed pattern, said power units having intakeand exhaust ports therein, two opposed pistons in each of said powerunits controlling said ports therein, 'and three cranks disposed apiecein three corners or'` said pattern, each crank having two pistons, onefrom each two associated power units, operatively journalledtheretoLsaid cranks being timed to reach simultaneously the dead centerwith respect to different power units whereby the piston controllingsaid exhaust port in any one power unit will precede the twin pistoncontrolling said intake port therein by an interval of approximately60degrees of crank rotation.

17, In a vpiston engine in combination in one plane, three cylindersdisposed to form an equilateral triangle, said cylinders having intakeand exhaust ports therein, two opposed pistons in each of said cylinderscontrolling said ports therein, and three cranks disposed apiece in theycorners of said triangle, each crank having two pistons, one from eachtwo associated cylinders, operatively journalled thereto, said' cranksbeing timed to reach simultaneously the deadcenter K aosaaro therein,two opposed pistons in each of said power units controlling. said portstherein, a number of cranks equal to the number o-f said power units inone pattern, said cranks constituting as many crankshafts disposed inthe corners of said patterns, each of said cranks having two pistons,one from each two associated power units, operatively journalledthereto, and means for timing .said crankshafts in rotation in a mannerwhereby the cranks in any y one pattern will reach simultaneouslythedead center with respect to different power umts therein whereby thepiston controlling said exhaust port will precede the twinpistoncontrolling said intake port in any one power unit by a limitedinterval, said power units being directed axially between the endsthereof so that the angle included by and between each two associatedpower units in any one pattern will be smaller than 90 degrees toprovide said limited interval.

, 19. A piston engine comprising, three cylinders disposed to form atriangle in one plane, a' number of like cylinders set in like trianglesside by side, said cylinders having intake and exhaust ports therein,two opposed pistons in each of said cylinders Vcontrolling said portstherein, three cranks disposed apiece in the corners of each triangleand constituting three crankshafts, each crank having two pistons, onefrom each two associated cylinders, operatively journalled thereto, andmeans for timing said crankshafts in rotation in a manner whereby thecranks in any one triangle will all reach simultaneously thedead centerwith respect todifferent cylinders therein whereby the pistoncontrolling said exhaust port will precede thetwin piston controllingsaid intake port in any one cylinder by an interval of approximatelydegrees.

20. In a piston engine in combination in one plane, three tubular unitsopen at bothends thereof, two opposed pistons in each of said units, twocranks positioned one at each end of said units, said pistons beingoperatively journalled each to one crank, said units being disposed toform jointly a closed pattern wherein each two associated units sharethe sam'e crank.

\ 21. In a piston engine in combination in one plane, three cranks, twopistons operatively Vjournalled to each of said cranks, three tubularunits open at both ends thereof, said units being disposed vbetween saidcranks to 'form jointly a closed pattern, said two pistons journalled toeach crank reciprocating in two associated units in said pattern.

22. In-a piston engine in combination in one plane, three cranks, twopistons operatively journalled to each of saidrcranks, three cylindersopen at both ends thereof, said cylinders being disposed between saidcranks to form jointly al triangular pattern, said two pistonsjournalled to each crank reciprocating in two assof ciated units in saidpattern.

23. In a piston engine in combination in one plane, three tubular unitsopen at both ends thereof, a pair of opposed pistons in each of saidunits, three cranks, said units being disposed to contact at said openends thereof, said cranks being positioned apiece at said contactingvends of said units, and two pistons, one from each two contacting units,operatively journalled to each crank.

24. In a piston engine in combination in one plane, three cylinders openat both ends thereof,

`lar pattern, a pair of opposed pistons in each of said power units, andthree cranks in said pattern whereby two pistons, one from each twoassociated units, will operate each crank.

26. In a-piston engine in combination in one plane, three power unitsopen at both ends thereof and disposed to form jointly a closed pattern,three cranks positioned apiece in the corners of said pattern, and twoopposed pistons in each of said power umts providing a combustion vorpressure chamber therebetween, each of said twin pistonsbeingfoperatively journalled to a different Vcrank in said pattern.

27. In a piston engine in combination, three V-type engines having eacha crankcase, two cylinders thereon in one plane and in any number oflike planes side-by-side, and one piston in each cylinder, each o f saidengines being disposed inversely tothe others, each cylinder in each Vbeing conjoined vwith one cylinder in the associated two Vs in a commoncombustion or pressure chamber between the pistons therein.

28. In a piston engine in combination, at least three engines havingeach a crankshaft in a crankcase, two cylinders forming a V thereon inone plane and in any number of like planes side by side, the angle insaid V being smaller than 90 degrees, one piston in each cylinderoperatively journalled to said crankshaft, each of said engines beingdisposed inversely to the others and each cylinder in ea'ch V being'conjoined with one cylinder in the associated Vs in a common combustionchamber between said pistons therein, and means for timing saidcrankshafts in rotation whereby the two pistons facing each other ineach combustion chamber will be outl of phase by a number of degrees ofcrank rotation equal to said limited angle inincluded in the Vs.

29. In a piston engine in combination, four V-type engines having eacha. crankcase, two cylinders thereon in one plane and-in any number oflike planes side-by-side, and one piston in each cylinder, each of saidengines being disposed inversely to the others and each cylinder in eachV being conjoined with one cylinder in two of the associated Vs in acommon combustion or pressure chamber between the pistons therein, theangle between the cylinders in any one V being less than 90 degrees.

30. A piston engine comprising, three power units open at both endsthereof, two opposed from each two adjacent power units, operativelyjournalled to each crank, and a number of like power units disposed inlike patterns side-by-side with said cranks united into threecrankshafts. 31. A piston engine comprising, three power units open atboth ends thereof and disposed to form jointly a closedy pattern in oneplane, two opposed pistons in each of said power units providing acombustion or pressure chamber therebetween, a crank positioned in eachcorner of said pattern, two pistons, one from' each two adjacent powerunits, operatively journalled to each crank, and means for timing saidcranks in rotation whereby said twin pistons in each power unit willreciprocate in opposite directions throughout the major portion of thestroke thereof and in the same direction throughout the remainder of it.

32. A piston .engine comprising, three -power .units open at both endsthereof and disposed to form jointly a triangular pattern in one plane,two opposed pistons in eachpower unit providing a combustion or pressurechamber therebetween, three cranks pertaining to as many crankshaftsdisposed apiece in the corners of said pattern-at right angles to theplane thereof, two pistons, one from each two adjacent power units,operatively journalled to each crank, means for timing said crankshaftsin rotation whereby said twin pistons in each power unit willJreciprocate in opposite directions throughout the major portion of thestroke thereof and in the same direction throughout the remainder ofit,-and a plurality of like power units disposed side-by-side in likepatterns between said crankshafts. 33. In a piston engine, a number ofpower units open at both ends thereof and disposed to forms jointly aclosed polygonal pattern in one plane wherein the included angle betweeneach 40 two associated power units is less than 90 degrees, said powerunits having exhaust and intake ports therein, two opposed pistons ineach power unit providing a combustion chamber therebetween, a number ofcranks equal to the number of said power units positioned apiece in thecorners of said pattern, 'two pistons, one from each two adjacent powerunits, operatively K. journalled to each crank, means fortiming saidcranks in rotation whereby said twin ,pistons in each power unit willtravel out-of-pliase by a number of degrees of crank rotation equaltosaid included angle between the power units, the piston controllingsaid exhaust port preceding the twin controlling said intake port, aninduction manifold in the space between said power units, said manifoldcomprising a central duct open at one axial end therof and passagesconnecting said intake ports therewith, and means for feeding saidinduction mamma with scavenging air, said timing means for said cranksand said feedpositeends of said engine.

34, A piston engine comprising, a number of power units open at bothends thereof and disposed to form jointly a closed polygonal pattern inone plane wherein the included angle between eachtwo associated powerunits is less than degrees, said power units having exhaust and intakeports therein, two opposed pistons in each power unit providing acombustion chamber therebetween, a number of cranks equal to the numberof said power units and pertaining to as many crankshafts positionedapiece in the corners of said pattern at right angles to the adjacentpower units, operatively journalled to each crank, a plurality of likepower units disposed side-by-side in like patterns between saidcrankshafts, means at one end.V of said engine for timing saidcrankshafts in rotation whereby said twin pistons in each power unitwill travel outof-phase by a number of degrees of crank rotation equalto said included angle between the power units, the piston controllingsaid exhaust port preceding the twin controlling said intake port, andinduction manifold located in the space between said power unitsconnecting to said intake ports therein, and means for feeding saidmanifold with scavenging' air from one end Y ing means for said manifoldbeing located at opf plane thereof, two pistons, one from each two` ofsaidy engine opposite to said end with said timing means thereat.

35. A piston engine comprising, three cylindrical power units open atboth ends thereof and disposed to jointly form a triangle in one plane,two opposed pistonsin each power unit"provid ing a combustion chambertherebetween, three crankshafts positioned apiece in the corners of jsaid triangle at right angles to the plane thereof 40 and having each acrank in saidplane, two pistons, one from each two adjacent power units,being operatively journalled to each crank, a plurality of like powerunits disposed in like tri- `angles side by side between saidcrankshafts.

means at one end of said engine for timing said crankshafts in rotationwhereby said twin pistons in each power unit will reciprocate inopposite directions throughout the major portion of I the strokethereof, intake and exhaust ports in said power units, an inductionmanifold located in the space between said power `units and connectingtov said intake ports therein, and means for feeding said manifold withscavenging air from the end of said engine opposite said end with saidtiming means thereat.

.JOHNv rAVLEcKA.

